Hello John
If your main concern is the type of device that will play the role of the BSR, then you don’t have to worry too much. The primary role of the BSR is to share RP information throughout a PIM domain. Routers wanting to become the RP for a group will send their candidacy to the BSR. The BSR then creates a list of these RPs and sends this list to all PIM routers in the domain. The BSR itself does not keep track of multicast routes: its main function is RP discovery. Its job is not resource-intensive.
The RPs are more of a concern when it comes to the capacity to handle multicast routes. They should be capable enough to support the amount of traffic that you expect. They should be relatively centrally placed in the topology because initially, they do route the multicast traffic. Once that’s done, traffic can then switch over to the SPT for more efficient routing, which is standard sparse mode operation.
The project sounds very interesting and I’m sure it will be an excellent experience for you to further your understanding of these topics. Let us know how you get along, and if you have any other questions feel free to post them here!
I hope this has been helpful!
Laz